# Who says you don't need a computer?

**Computer Science**Level 4

Euler's Phi function is a function \(\phi : \mathbb{N} \rightarrow \mathbb{N}\) which when applied to a natural number \(n\), gives the number of natural numbers less than or equal to \(n\) that are coprime to \(n\).

Find \(\displaystyle \sum_{n=1}^{1000} \phi(n) \)

**Suggestions**:-

Solve this with a program in language you like, rather than using a calculator (Programming practice) ..... Make use of the properties of the Phi function.